fuel injection strategy for soot-filter regeneration
TRANSCRIPT
![Page 1: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/1.jpg)
DEER CONFERENCE 2008 1
Fuel Injection Strategy for Soot-Filter Regeneration
Fabien A. RioultFlorian Von TrentiniMarius Vaarkamp
![Page 2: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/2.jpg)
DEER CONFERENCE 2008 2
Outline
•
Regeneration of Soot Filters
•
Causes of Soot Filter Failures
•
Modeling of Active Regeneration and Drop-to-Idle events
•
Injection Strategy
•
Conclusion
![Page 3: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/3.jpg)
DEER CONFERENCE 2008 3
Soot Filters in Diesel Exhaust Systems
• Soot thickness increases with time
•
Backpressure in the exhaust system increases = loss of engine power
• Overload can clog the filter
Soot cake
As the soot accumulates in the filter, the backpressure of the exhaust increases. The soot needs to be removed continuously or periodically.
![Page 4: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/4.jpg)
DEER CONFERENCE 2008 4
Passive and Active Regeneration The exhaust temperature is not always hot enough to regenerate
passively the soot filter. Then, active regeneration becomes necessary.
NOCONOC(soot)NO 2CO NO 2 C(soot)
2
22
+→++→+
COO21C(soot)
CO O C(soot)
2
22
→+
→+
Passive Regeneration (optimal at ≈300oC)
Active Regeneration (>550oC)[DieselNet.com]
22 NOO21NO →+
DOC CSF
Fuel injector
![Page 5: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/5.jpg)
DEER CONFERENCE 2008 5
High Temperature is a Risk of Failure for Soot Filters
•
Loss of catalytic activity
•
Sintering of PM particles
•
Alumina polymorphic transformation (1100oC)
•
Ash reaction with cordierite
•
Solid-state reaction with cordierite (1200oC)
•
Filter-ash eutectic
•
Mechanical stress
•
Thermal gradients
•
Fatigue
•
Melting point of Cordierite (1450oC) [Photos from
DieselNet.com]
![Page 6: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/6.jpg)
DEER CONFERENCE 2008 6
Drop-to-Idle: Sudden drop of the exhaust gas flow rate during an active regeneration. The heat from the soot oxidation accumulates in the CSF and leads to a runaway reaction.
• Sudden drop of the exhaust flow rate
Flow
HC Injection
t
D
Variable
Variable
![Page 7: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/7.jpg)
DEER CONFERENCE 2008 7
Speed = x 30
Active Regeneration SimulationAs the temperature increases in the CSF, the soot regeneration rate increases.
Time
![Page 8: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/8.jpg)
DEER CONFERENCE 2008 8
Active Regeneration with Drop-to-Idle Simulation
Speed = x 60
The flow rate is too low to evacuate the heat created by the soot oxidation.
Time
![Page 9: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/9.jpg)
DEER CONFERENCE 2008 9
Filter Model (BASF CatSim) / Assumptions
CO, HC, NO, NH3,…
P, T, F CO2, H2O, N2, NO2, …
Heat and MassTransfer
Thermal losses to ambient
Axial conduction
Thermal conduction to can
Reactions
Soot Accumulation
Soot Regeneration
•
Soot oxidation yields equal amounts of CO and CO2 (CO is converted over the PM function of the catalyst)
•
No axial motion of the soot from the cake•
1D Model (no radial temperature gradients)•
Homogeneous soot distribution•
Uniform deactivation
![Page 10: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/10.jpg)
DEER CONFERENCE 2008 10
Active Regeneration - DOC+ CSF - 600C DOC out - 3.9g/l soot loading
300
400
500
600
700
800
900
200 300 400 500 600 700 800 900 1000 1100 1200Time (s)
Tem
pera
ture
(C)
TC_25mmTC_152mmTC_279mmTC_406mm60 C
Thick line: model
Thin line: experiments
Comparison of Model to Experimental Results. The model underestimates the maximum temperature in the CSF
during an active regeneration (radial thermal gradients are not considered).
23K/hr
![Page 11: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/11.jpg)
DEER CONFERENCE 2008 11
Fuel Injection Strategy: Objectives
•
Propose an injection strategy for active regeneration with the following constraints:
•
The maximum temperature in the CSF during a drop-to-idle event must not be higher than 700oC.
•
Reach 90% regeneration.
•
Decrease the duration of the regeneration.
![Page 12: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/12.jpg)
DEER CONFERENCE 2008 12
Experimental Conditions
•
Initial soot loading: 3.5 gm/l
•
Inlet Gas Temperature: 280oC
•
Constant filter dry gain of 0.25 gm/in3
•
Drop-to-Idle: 10 to 3 K/hr ; 20 to 3 K/hr Uniform DOC, 300/8, 12”x8”
PM : 60 gm/ft3
(4:1)
Uniform CSF, 270/16, 13”x17”
PM : 1.2 gm/ft3
(4:1)
DOC + CSF
![Page 13: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/13.jpg)
DEER CONFERENCE 2008 13
Drop-to-Idle Test (DTI)
•
The flow is decreased from 125 gm/s to 35 gm/s and the HC injection is decreased to 0 gm/s after a variable duration D.
•
Several scenarios (different injection duration D) of drop-to-idle are considered in order to obtain the worst case.
10 to 3K/hr
Flow
HC Injection
tD
Variable
Variable
X
The maximum temperature in the CSF during drop-to-idle test has been calculated for variable injection rates and duration.
![Page 14: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/14.jpg)
DEER CONFERENCE 2008 14
Drop-to-Idle Test (DTI)
10 to 3K/hr
Flow
HC Injection
tD
Variable
Variable
X
Flow
HC Injection
tD
Variable
Variable
X
Increasing the injection rate during the regeneration will allow to avoid high temperatures in case of DTI.
CSF-in: 570oC
CSF-in: 520oC
CSF-in: 560oC
X:
![Page 15: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/15.jpg)
DEER CONFERENCE 2008 15
Comparison between a Constant Injection and a Staged Injection.
Fuel injection rate
Time
X
reference
90 sec
3 step injection
As the soot is consumed, the injection rate can be increased. The following injection represent a 3 additional step injection respectively corresponding to 110, 120 and 130 % of the initial injection. The duration of the steps has been adjusted so that the maximum drop to idle temperature never reaches 700oC.
Fuel injection rate
![Page 16: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/16.jpg)
DEER CONFERENCE 2008 16
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400Time (s)
Reg
ener
atio
n (%
)
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Fuel
inje
cted
(gm
)
3 steps - Fuel injected (gm)3 steps - Regeneration (%)
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400Time (s)
Reg
ener
atio
n (%
)
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Fuel
inje
cted
(gm
)
3 steps - Fuel injected (gm)Reference - Fuel injected (gm)3 steps - Regeneration (%)Reference - Regeneration (%)
The staged injection shows a significantly shorter regeneration time and lower fuel consumption than the reference injection.
Constant VS Staged Injection: SV (10K/hr)
d0
=260sd1= d2
=100s
10K/hr
10 min
42% time economy
10 min
42% time economy
38% fuel economy
38% fuel economy
90% Regeneration
16 minutes
90% Regeneration
16 minutes
![Page 17: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/17.jpg)
DEER CONFERENCE 2008 17
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400Time (s)
Reg
ener
atio
n (%
)
0
500
1000
1500
2000
2500
3000
Fuel
inje
cted
(gm
)
3 steps_Fuel injected (gm)
Reference_Fuel injected (gm)
3 steps_Regeneration (%)
Reference_Regeneration (%)
The staged injection shows a significantly shorter regeneration time and lower fuel consumption than the reference injection.
Constant VS Staged Injection :SV (20K/hr)
d0
=260sd1= d2
=100s
20K/hr
11 min
46% time economy
11 min
46% time economy
43% fuel economy
43% fuel economy
90% Regeneration
14 minutes
90% Regeneration
14 minutes
![Page 18: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/18.jpg)
DEER CONFERENCE 2008 18
Staged injection : DTI testDrop-to-idle events have been simulated for variable injection duration during this stepped injection.
Fuel injection rate
Time
X 1.1X
d0
3 steps
90 sec
d1d2
1.2X 1.3X
D(s), injection time before drop-to-idle140 sec
20 to 3K/hr
10 to 3K/hr
![Page 19: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/19.jpg)
DEER CONFERENCE 2008 19
The staged injection strategy allows to keep the maximum temperature of the uniform CSF (with upstream DOC) below 700oC whenever the drop-to-idle event occurs.
10 to 3K/hr
400
450
500
550
600
650
700
750
800
850
900
0 100 200 300 400 500 600 700D (s)
Max
. Tem
p in
CSF
(C)
3 steps - 10K/hr
3 steps - 20K/hr
20 to 3K/hr
Staged injection : DTI test
![Page 20: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/20.jpg)
DEER CONFERENCE 2008 20
Conclusion / Path Forward
• Staged injection strategy allows:
•
to respect a desired maximum temperature in the CSF when a drop-to-idle event occurs (700oC for this study).
• to decrease the fuel consumption
• to decrease the regeneration duration = decrease risk of DTI
•
A better tuning of the steps duration or the addition of intermediary steps (or even using a continuous function) would allow further improvement of the regeneration.
•
Experimental verification of the injection strategy (Model results validation)
•
Steady-state → Transient
Path Forward
Conclusions
![Page 21: Fuel Injection Strategy for Soot-Filter Regeneration](https://reader031.vdocuments.us/reader031/viewer/2022021212/62065bbd8c2f7b1730070034/html5/thumbnails/21.jpg)
DEER CONFERENCE 2008 21
Acknowledgement
Florian Von Trentini
Dennis Anderson
Marius Vaarkamp
Sanath Kumar
Ken Voss
Alfred Punke
Kevin Hallstrom
Joe Patchett
Matt Larkin
Maurica Fedors